Dendreon Announces Presentation of PROVENGE® (sipuleucel-T) and DN24-02 Immuno-Oncology Data at the 2014 ASCO Annual Meeting

<0> Dendreon CorporationLindsay Rocco, 862-596-1304Corporate Communications </0>

May 14, 2014– Dendreon Corporation (NASDAQ:) announced today the presentation of two PROVENGE (sipuleucel-T) abstracts from the Phase II STAND study and the PROCEED registry, and one abstract highlighting data from the ongoing Phase II study of DN24-02, an investigational active cellular immunotherapy for patients with surgically resected HER2+ urothelial cancer. These data will be presented at the 50 Annual Meeting of the American Society of Clinical Oncology (ASCO) from May 30-June 3, 2014 in Chicago, Illinois.

Additionally, preliminary data from the Phase II STRIDE study evaluating concurrent or sequential treatment of PROVENGE with enzalutamide are available online at .

“These data continue to help reinforce how PROVENGE may be combined or sequenced with other advanced prostate cancer treatments,” said Andrew S. Sandler, M.D., executive vice president and chief medical officer at Dendreon. “We remain committed to our active cellular immunotherapy platform and expanding the medical community’s understanding of how immuno-oncology treatments can be used to benefit patients.”

Dendreon will present the following studies evaluating PROVENGE and DN24-02 data at ASCO:

“These data support the current clinician perception that the future of cancer treatments should be a personalized approach, including immunotherapies,” said Daniel Petrylak, M.D., professor of medicine, director of Genitourinary Oncology, co-director of Signal Transduction Research Program, Yale Cancer Center and Smilow Cancer Hospital at Yale-New Haven. “We continue to see powerful evidence of meaningful immunological responses to immunotherapies such as sipuleucel-T and investigational compound DN24-02.”

PROVENGE (sipuleucel-T) is an autologous cellular immunotherapy indicated for the treatment of asymptomatic or minimally symptomatic metastatic castrate resistant (hormone refractory) prostate cancer. PROVENGE is intended solely for autologous use and is not routinely tested for transmissible infectious diseases.

The safety evaluation of PROVENGE was based on 601 prostate cancer patients in four randomized clinical trials who underwent at least one leukapheresis. The most common adverse events (incidence greater-than or equal to 15%) are chills, fatigue, fever, back pain, nausea, joint ache, and headache. Serious adverse events reported in the PROVENGE group include acute infusion reactions (occurring within 1 day of infusion) and cerebrovascular events. In controlled clinical trials, severe (Grade 3) acute infusion reactions were reported in 3.5% of patients in the PROVENGE group. Reactions included chills, fever, fatigue, asthenia, dyspnea, hypoxia, bronchospasm, dizziness, headache, hypertension, muscle ache, nausea, and vomiting. No Grade 4 or 5 acute infusion reactions were reported in patients in the PROVENGE group.

To fulfill a post marketing requirement and as a part of the company’s ongoing commitment to patients, Dendreon will conduct a registry of approximately 1,500 patients to further evaluate a small potential safety signal of cerebrovascular events. In four randomized clinical trials of PROVENGE in prostate cancer patients, cerebrovascular events were observed in 3.5% of patients in the PROVENGE group compared with 2.6% of patients in the control group.

For more information on PROVENGE, please see the full prescribing information at or call 1-877-336-3736.

Dendreon Corporation is a biotechnology company whose mission is to target cancer and transform lives through the discovery, development, commercialization and manufacturing of novel therapeutics. The Company applies its expertise in antigen identification, engineering and cell processing to produce active cellular immunotherapy (ACI) product candidates designed to stimulate an immune response in a variety of tumor types. Dendreon’s first product, PROVENGE(sipuleucel-T), was approved by the U.S. Food and Drug Administration (FDA) in April 2010. Dendreon is exploring the application of additional ACI product candidates and small molecules for the potential treatment of a variety of cancers. The Company is headquartered in Seattle, Washington, and is traded on the NASDAQ Global Market under the symbol DNDN. For more information about the Company and its programs, visit .